Measuring the amount of corrosion inhibitor added to a non-aqueous, non-conductive liquid, such as ethanol, gasoline, or blends of gasoline and ethanol, can be a problem. Conventional corrosion inhibitors are also non-conductive. Thus, the content of non-conductive inhibitors in non-aqueous, non-conductive liquid cannot be measured by conventional methods. Conventional methods for measuring ingredients in flowing liquids employ apparatus such as a magnetic flow meter that require that the liquid have a conductivity greater than 5 microSiemens per centimeter.
The conversion of corn into fuel ethanol is gaining popularity. In the United States, more than 135 plants produce ethanol. Currently, many ethanol plants use magnetic flow meters to measure the flow of beer from the fermenter to the distillation columns. Magnetic flow meters work by applying a magnetic field to a metering tube, which results in a potential difference proportional to the flow velocity perpendicular to the flux lines. Magnetic flow meters can only measure the flow of fluids in which some solids are present or those having a high concentration of ions and generally do not work with non-aqueous solutions. Once distilled ethanol leaves the columns, a magnetic flow meter will not accurately measure flow because there are no solids present in the ethanol and ethanol has low conductivity.
Distilled ethanol is corrosive to metals and can cause mass change, pitting, or degradation of metal pipes, storage tanks, and gas tanks. Corrosion inhibitors are often added to ethanol following distillation to prevent this corrosion. Conventional corrosion inhibitors are non-conductive, are too viscous, can increase the viscosity of a non-aqueous, non-conductive liquids, such as ethanol, and can separate from such liquids.
Accordingly, there remains a need for corrosion inhibitors for non-aqueous, non-conductive liquids that can be detected by conventional apparatus.